Detection And Analysis Of Intestinal Flora Diversity In Patients With Anal Fistula

Objective The aim of this study was to detect bacterial species in the stool samples of patients with cryptogenic anal fistula with 16S rDNA gene sequencing,comparing these with controls,to further reveal the relevant mechanism of the occurrence and development of anal fistula.Method Stool samples were obtained from 30 patients with cryptogenic anal fistula(Group 1)and 30 controls without gastrointestinal disease(Group 2).The total bacterial genomic DNA was extracted with PCR amplification of the V4 hypervariable region in the bacterial 16S rRNA gene sequence.High-throughput sequencing was performed on the Illumina Miseq platform with data analysis.Results The alpha diversity analysis(ACE,Chao,Shannon and Simpson index)showed a consistently richer diversity of intestinal microflora in Group 1 cases when compared with Group 2 controls.Beta diversity analysis showed a consistently broader diversity of intestinal microflora in Group 1 when compared with Group 2.There was a greater abundance of spp.Prevotella(4.9%vs.0.1%,P<0.01),Megamonas(3.9%vs.0.5%,P<0.01)and Lachnospira(2.6%vs.0.1%,P<0.01)with fewer spp.Proteobacteria(4.2%vs.10.9%,)and Enterococcus(0.02%vs.9.3%,respectively P<0.01).The main strains of Veillonellaceae,Selenemondales and Negativicutes(all belonging to the phylum Firmicutes)have overall the greatest influence on these group differences.Conclusion There are significant differences in the types of bacteria in stool samples between patients with anal fistula and healthy people.The abundance of Prevotella,Megamonas and Lachnospira in the anal fistula group is significantly higher than that in the healthy group,which may be related to the occurrence and development of anal fistula.